Planck's law

As we saw above, Planck's law of black body radiation dictates that an object's temperature determines its color.

In such cases Planck's law still applies, but the resulting glow will be of a color beyond the range to which our eyes or ordinary telescopes are sensitive.

We can see this effect, known as "Planck’s law of black body radiation," in action whenever we look at the different colors of stars.

In this and subsequent studies, astronomers have been able to make a precision measurement of the star’s color, and then have used Planck's law of black body radiation to calculate its temperature.

He wanted to know how I had hit upon the idea of deriving Planck's law in this way.